Alteration of cerebrovascular haemodynamic patterns due to atrial fibrillation: an in silico investigation

Abstract

There has recently been growing evidence that atrial fibrillation (AF), the most common cardiac arrhythmia, is independently associated with the risk of dementia. This represents a very recent frontier with high social impact for the number of individuals involved and for the expected increase in AF incidence in the next 40 years. Although a number of potential haemodynamic processes, such as microembolisms, altered cerebral blood flow, hypoperfusion and microbleeds, arise as connecting links between the two pathologies, the causal mechanisms are far from clear. An in silico approach is proposed that combines in sequence two lumped-parameter schemes, for the cardiovascular system and the cerebral circulation. The systemic arterial pressure is obtained from the cardiovascular system and used as the input for the cerebral circulation, with the aim of studying the role of AF on the cerebral haemodynamics with respect to normal sinus rhythm (NSR), over a 5000 beat recording. In particular, the alteration of the haemodynamic (pressure and flow rate) patterns in the microcirculation during AF is analysed by means of different statistical tools, from correlation coefficients to autocorrelation functions, crossing times, extreme values analysis and multivariate linear regression models. A remarkable signal alteration, such as a reduction in signal correlation (NSR, about 3 s; AF, less than 1 s) and increased probability (up to three to four times higher in AF than in NSR) of extreme value events, emerges for the peripheral brain circulation. The described scenario offers a number of plausible cause-effect mechanisms that might explain the occurrence of critical events and the haemodynamic links relating to AF and dementia.

Atrial Fibrillation and Cognitive Impairment: New Insights and Future Directions

“…Accordingly, they claimed a reduction in signal correlation about 3 s for NSR and less than 1 s for AF, as well as an increased probability (up to three to four times higher in AF vs. NSR) of extreme value events emerging for brain circulation. These studies [58,61] corroborated the impact of AF on cerebral haemodynamics as a proper mechanism for the progression of AF-related CIM/dementia.…”

“…Moreover, Figure 1 Different possible mechanisms through which atrial fibrillation may contribute to cognitive impairment. Scarsoglio et al [61] shed light on the role of AF on cerebral haemodynamics concerning normal sinus rhythm (NSR), via an in silico approach. Accordingly, they claimed a reduction in signal correlation about 3 s for NSR and less than 1 s for AF, as well as an increased probability (up to three to four times higher in AF vs. NSR) of extreme value events emerging for brain circulation.…”

Control of ventricular rate in permanent atrial fibrillation: cardio­protec­tion and tissue hemodynamics

“…Замедление кровотока в терминальном звене сосудистой сети способствует повышению вязкости крови и возрастанию напряжения сдвига, являясь одной из причин развивающейся на фоне ФП дисфункции эндотелия. Длительное воздействие этих факторов может приводить к декомпенсации механизмов продукции оксида азота и прогрессированию локального про-тромботического состояния, что в церебральном кровотоке увеличивает риск развития ишемического инсульта [35].…”

From time-series to complex networks: Application to the cerebrovascular flow patterns in atrial fibrillation

“…The computational approach has been validated mainly over mean flow rates up to the middle cerebral circulation 36 , since current clinical techniques for pressure and flow rate measures lack the resolving power to give any insights on the micro-vasculature. For this reason, the cerebral modeling can be a useful predictive tool to understand how the hemodynamic signals change towards the micro-circulation in presence of AF 36,37 . The left vascular pathway ICA-MCA (i.e., internal carotid artery -middle cerebral artery) evidenced in Fig.…”